1. Field of the Invention
The present invention relates to building materials, in particular to manufacturing light, stable and hollow man-made bricks and stones for brickwork.
2. Description of the Related Art
Known is a method of manufacturing building brick and stone (RU 2233815 (2002)), according to which a batch of carbonated sandy clay (85-90%) and micro-silica (10-15 wt. %) is prepared and exposed to granulation in the presence of water solution of sulphate soap. Obtained granulated compound is molded, dried and burnt at 950° C.
Also known is a method of manufacturing facing bricks tiles (RU 2070177 (1996)), which includes wet milling of manufacturing waste products (10-15 wt. % of broken glass and 10-15 wt. % of thermophosphate slag), its blending with 32.5 wt. % of high-quality and 32.5 wt. % of low-grade (sand-mixed) clay, further milling, and drying. Obtained is a 4-8 wt. % humid granulated molding compound, which is exposed to half-dry molding and burn.
There is a method of manufacturing ceramic bricks for wall incrustation (RU 2036880 (1995)), according to which a batch is first prepared comprising the following components (wt. %) clay slate (60-80), pearlite or obsidian (5-20) or broken glass (5-20), quicklime (5-10) and as much of solution of sodium hydroxide. The forming of compound is realized by half-dry method, applying 22-4 MPa pressure. The obtained bricks are dried down to 1% residual moisture and burnt, the temperature raising at 200-300° C. an hour and staying at 750-800° C. for 1-3 hours.
The material thus obtained possesses the following parameters: water absorption 2-10%, freeze-thaw resistance 25-50 cycles, compressive strength of 22-45 MPa.
This method has a number of drawbacks. The bricks are not strong enough to use them as load-bearing ones. A large proportion of clay used, with shrinkage characteristic therefor, requires prior slow drying of bricks to avoid cracking during burn. The use of quicklime complicates the manufacturing process and requires big expenditures of energy associated with limestone burn and crushing lime.